Field of the Invention
The field of the invention includes flush toilets, and more particularly certain gravity-powered wash down or siphonic flush toilets having a cleaning system with a cleaning cycle.
Description of Related Art
There are a wide variety of types of toilets and toilet assemblies having toilet bowls, including gravity-powered siphonic and wash down toilets. Siphonic toilets may include rim-fed bowls, non-jetted, rim-jetted and direct jetted bowls. Such, toilets for removing waste products, such as human waste, are well known. Typically, toilets such as gravity-powered toilets generally have two main parts: a tank and a bowl. The tank and bowl can be separate pieces coupled together to form the toilet system (commonly referred to as a two-piece toilet) or can be combined into one integral unit (typically referred to as a one-piece toilet).
The tank, if present, is usually positioned over the back of the bowl, contains water that is used for initiating flushing of waste from the bowl to the sewage line, as well as refilling the bowl with fresh water. When a user desires to flush the toilet, he pushes down on a flush lever on the outside of the tank, which lever is connected on the inside of the tank to a movable chain or lever within the tank. When the flush lever is depressed, it moves a chain or lever on the inside of the tank that acts to lift and open the flush valve, causing water to flow from the tank and into the bowl, thus initiating the toilet flush. Other toilets operate without a tank using in-line plumbing fed from a water source and in-line flush valves which actuate by action of an actuation device such as a flush handle, a push button, or the like.
There are three general purposes to be served in a flush cycle. The first is to remove any solid, liquid or other waste to the drain line. The second is cleansing the bowl to remove any solid, liquid or other waste which was deposited or adhered to the surfaces of the bowl during use. The third is exchange of pre-flush water in the bowl so that relatively clean water remains in the bowl between uses restoring the seal depth against backflow of sewer gas, and readying the toilet for the next use and flush cycle.
The second requirement, cleansing of the bowl, is usually achieved by way of the hollow rim found in most toilets that extends around the upper perimeter of the toilet bowl. Some or all of the flush water is directed through such a hollow rim channel and flows through openings positioned therein to disperse water over the entire surface of the bowl and accomplish the required cleansing.
Gravity powered toilets can be classified in two general categories: wash down and siphonic. In a wash-down toilet, the water level within the bowl of the toilet remains relatively constant at all times. When a flush cycle is initiated, water flows from the tank or other water source and spills into the bowl. This causes a rapid rise in water level and the excess water spills over the weir of the trapway, carrying liquid and solid waste along with it. At the conclusion of the flush cycle, the water level in the bowl naturally returns to the equilibrium level determined by the height of the weir.
In a siphonic toilet, the trapway and other hydraulic channels are designed such that a siphon is initiated in the trapway upon addition of water to the bowl. The siphon tube itself is an upside down U-shaped tube that draws water from the toilet bowl to the wastewater line. When the flush cycle is initiated, water flows into the bowl and spills over the weir in the trapway faster than it can exit the outlet to the sewer drain line. Sufficient air is eventually removed from the down leg of the trapway to initiate a siphon which in turn pulls the remaining water out of the bowl. The water level in the bowl when the siphon breaks is consequently well below the level of the weir, and a separate mechanism needs to be provided to refill the bowl of the toilet at the end of a siphonic flush cycle to reestablish the original water level and protective seal preventing back flow of sewer gas.
Generally, siphonic and wash-down toilets have inherent advantages and disadvantages. Siphonic toilets, due to the requirement that most of the air be removed from the down leg of the trapway in order to initiate a siphon, tend to have smaller trapways which can result in clogging. Wash-down toilets can function with large trapways but generally require a smaller amount of pre-flush water in the bowl to achieve the 110:1 dilution level required by plumbing codes in most countries (i.e., 99% of the pre-flush water volume in the bowl must be removed from the bowl and replaced with fresh water during the flush cycle). This small pre-flush volume manifests itself as a small “water spot.” The water spot, or surface area of the pre-flush water in the bowl, plays an important role in maintaining the cleanliness of a toilet. A large water spot increases the probability that waste matter will contact water before contacting the ceramic surface of the toilet. This reduces adhesion of waste matter to the ceramic surface making it easier for the toilet to clean itself via the flush cycle. Wash-down toilets with their small water spots therefore frequently require manual cleaning of the bowl after use.
Siphonic toilets have the advantage of being able to function with a greater pre-flush water volume in the bowl and greater water spot. This is possible because the siphon action pulls the majority of the pre-flush water volume from the bowl at the end of the flush cycle. As the tank refills, a portion of the refill water is directed into the bowl to return the pre-flush water volume to its original level. In this manner, the 110:1 dilution level required by many plumbing codes is achieved even though the starting volume of water in the bowl is significantly higher relative to the flush water exited from the tank. In the North American markets, siphonic toilets have gained widespread acceptance and are now viewed as the standard, accepted form of toilet. In European markets, wash-down toilets are still more accepted and popular, whereas both versions are common in the Asian markets.
Gravity powered siphonic toilets can be further classified into three general categories depending on the design of the hydraulic channels used to achieve the flushing action. These categories are: non-jetted, rim-jetted, and direct-jetted.
In typical non jetted bowls, all of the flush water exits the tank into a bowl inlet area and flows through a primary manifold into the rim channel. The water is dispersed around the perimeter of the bowl via a series of holes positioned underneath the rim. Some of the holes may be designed to be larger in size to allow greater flow of water into the bowl. A relatively high flow rate is needed to spill water over the weir of the trapway rapidly enough to displace sufficient air in the down leg and initiate a siphon. Non-jetted bowls typically have adequate to good performance with respect to cleansing of the bowl and exchange of the pre-flush water, but are relatively poor in performance in terms of bulk removal. The feed of water to the trapway is inefficient and turbulent, which makes it more difficult to sufficiently fill the down leg of the trapway and initiate a strong siphon. Consequently, the trapway of a non-jetted toilet is typically smaller in diameter and contains bends and constrictions designed to impede flow of water. Without the smaller size, bends, and constrictions, a strong siphon would not be achieved. Unfortunately, the smaller size, bends, and constrictions result in poor performance in terms of bulk waste removal and frequent clogging, conditions that are extremely dissatisfying to end users.
Designers and engineers of toilets have improved the bulk waste removal of siphonic toilets by incorporating “siphon jets.” In a rim-jetted toilet bowl, the flush water exits the tank, flows through the toilet inlet area and through the primary manifold into the rim channel. A portion of the water is dispersed around the perimeter of the bowl via a series of holes positioned underneath the rim. The remaining portion of water flows through a jet channel positioned at the front of the rim. This jet channel connects the rim channel to a jet opening positioned in the sump of the bowl. The jet opening is sized and positioned to send a powerful stream of water directly at the opening of the trapway. When water flows through the jet opening, it serves to fill the trapway more efficiently and rapidly than can be achieved in a non-jetted bowl. This more energetic and rapid flow of water to the trapway enables toilets to be designed with larger trapway diameters and fewer bends and constrictions, which, in turn, improves the performance in bulk waste removal relative to non jetted bowls. Although a smaller volume of water flows out of the rim of a rim jetted toilet, the bowl cleansing function is generally acceptable as the water that flows through the rim channel is pressurized by the upstream flow of water from the tank. This allows the water to exit the rim holes with higher energy and do a more effective job of cleansing the bowl.
Although rim jetted bowls are generally superior to non-jetted, the long pathway that the water must travel through the rim to the jet opening dissipates and wastes much of the available energy. Direct-jetted bowls improve on this concept and deliver even greater performance in terms of bulk removal of waste. Generally, in a direct-jetted bowl, the flush water exits the tank and flows through the bowl inlet and through the primary manifold. At this point, the water divides into two portions: a portion that flows through a rim inlet port to the rim channel with the primary purpose of achieving the desired bowl cleansing, and a portion that flows through a jet inlet port to a “direct-jet channel” that connects the primary manifold to a jet opening in the sump of the toilet bowl. The direct jet channel can take different forms, sometimes being unidirectional around one side of the toilet, or being “dual fed,” wherein symmetrical channels travel down both sides connecting the manifold to the jet opening. As with the rim jetted bowls, the jet opening is sized and positioned to send a powerful stream of water directly at the opening of the trapway. When water flows through the jet opening, it serves to fill the trapway more efficiently and rapidly than can be achieved in a non jetted or rim jetted bowl. This more energetic and rapid flow of water to the trapway enables toilets to be designed with even larger trapway diameters and minimal bends and constrictions, which, in turn, improves the performance in bulk waste removal relative to non-jetted and rim-jetted bowls.
In addition to the types of toilets and their cleaning capability, there is pressure to use less water, making the cleaning function more difficult. Government agencies continually demand that municipal water users reduce the amount of water they use. Much of the focus in recent years has been to reduce the water demand required by toilet flushing operations. In order to illustrate this point, the amount of water used in a toilet for each flush has gradually been reduced by governmental agencies from 7 gallons/flush (prior to the 1950's), to 5.5 gallons/flush (by the end of the 1960's), to 3.5 gallons/flush (in the 1980's). The National Energy Policy Act of 1995 now mandates that toilets sold in the United States can use water in an amount of only 1.6 gallons/flush (6 liters/flush). Regulations have recently been passed in the State of California which require water usage to be lowered ever further to 1.28 gallons/flush. The 1.6 gallons/flush toilets currently described in the patent literature and available commercially lose the ability to consistently siphon when pushed to these lower levels of water consumption. Thus, manufacturers are being and will continue to be forced to reduce trapway diameters and sacrifice performance without development of improved technology and toilet designs.
Several inventions have thus been aimed at improving the flush performance of siphonic toilets through optimization of the direct jetted concept. For example, in U.S. Pat. No. 5,918,325, performance of a siphonic toilet is improved by improving the shape of the trapway. In U.S. Pat. No. 6,715,162, performance is improved by the use of a flush valve with a radiused inlet and asymmetrical flow of the water into the bowl.
U.S. Pat. No. 8,316,475 B2 demonstrates a pressurized rim and direct fed jet configuration for enhanced washing and adequate siphon for use with low volume water in accordance with current environmental water-use standards.
U.S. Patent Publication No. 2012/0198610 A1 shows a high performance toilet achieved by incorporating a control element in the area of the primary manifold to divide the flow of flush water entering the toilet manifold from the tank inlet into the inlet port of the rim and the inlet port of the direct-fed jet.
While the above concepts improve flush performance, and in some cases bowl cleaning as well, there are further attempts focused on improving bowl cleaning, such as that of co-pending Patent Application Publication No. 2013/0219605 A1, incorporated herein by reference, of the present applicant directed to a rimless bowl that provides enhanced cleaning without a traditional rim channel by directing all water either along an internal ledge from an inlet port or through the jet. Flow through the inlet port assists the washing function. The washing function is improved in this design.
Similarly, a toilet having a primed jet, and a rim flow path isolated from the jet flow path, as well as independent valves for the jet and rim flow paths is the subject of co-pending International Application No. PCT/US2013/069961 of the applicant herein in relevant part by reference with respect to the design and structure of the toilet, flush valves and valve backflow prevention structures therein. This application provides a toilet assembly that enables a strong flush and enhanced cleaning with very little water by minimizing air flow in the jet channel. This toilet may also be made in a rimless design with enhanced washing capability and can provide excellent cleaning.
While all improvements described above attempt to provide bowls that have strong flush capacity and good cleaning without having to clean overly much between flushing, there is still a need in the art for periodic manual cleaning of a toilet using a toilet bowl cleaning agent in the ordinary manner that consumers clean their toilet bowls. Toilet bowl brushes, gel cleaners, swaps, tablets and the like that are placed under the rim or in the tank directly or in a container are known.
Attempts have also been made to make such toilets “self-cleaning” by providing mechanisms for introduction of cleaning agent on a regular basis to work with each flush. Some such toilets have external systems that feed cleaning agent into the toilet bowl or into the rim using a controller or other external actuation mechanism. Others provide an internal reservoir with a cleaning agent or material, such as a tablet, that feeds slowly into the bowl with flush water through a tube within the overflow tube of a traditional flush valve. Programmable systems also exist that enable cleaning through the flush system.
U.S. Pat. Nos. 5,542,132, 5,608,923, 5,729,837, 5,867,844, and 5,913,611 are directed to use of a pump and controller that operates the flow of cleaning agent to the rim or bowl at a set timing and selected flow rate. In U.S. Pat. No. 5,729,837, a cleaning agent receptacle and pump are provided. The receptacle includes cleaning agent in fluid form that is pumped for cleaning after flushing into the rim directly after a flush cycle
U.S. Pat. No. 6,321,392 describes placing a cleaning agent in a reservoir within the tank and above the water level. The reservoir receives fluid by conduit from the refill valve water after a flush and cleaning agent is then combined with water that passes out of the refill valve and into the toilet through the overflow tube of the flush valve. The overflow tube introduces the flush water at the base of the interior body of the flush valve. The cleaning agent is introduced with every flush.
U.S. Pat. No. 5,745,928 discloses a reservoir positioned in a toilet tank in communication with the flush and fill valves. After the flush cycle, water flows as a bypass from the flush valve, through the reservoir (which has cleaning agent such as cleaning pellets within the reservoir) and down into the toilet through the refill tube. The cleaning agent sits in the bowl for extra cleaning.
U.S. Pat. No. 6,772,450 includes a chemical injector system with a timer and controller that feeds chemical solution in through flexible, shaped tubing positioned in the bowl below rim outlet holes. The chemical agent is injected in a pressurized manner into the bowl down the side walls to clean the bowl.
U.S. Pat. No. 8,095,997 discloses a modular mounted dispenser for cleaning fluid or deodorant introduced in a controllable manner into the toilet either through the overflow tube or directly into the tank water. The controller can be responsive to a level sensor.
While all such improvements have been made, the continuous introduction of cleaning fluid that works in various prior art systems to introduce cleaning agent with repeated flushing or that allows cleaning agent to sit in the bowl has not been well received by consumers, either due to complex external systems which are hard to operate or fill and/or as a result of the overuse of cleaning agents in the flush water which can prove harmful in high concentrations to pets and children if ingested. Further, overuse of cleaning agents over time can cause damage to the internal parts within the toilet bowl such as rubber seals and the like. Finally, some of such systems are not aesthetically pleasing and have many external parts that are within plain site of the user.
There is a need in the art for a self-cleaning toilet that can operate upon demand to minimize the impact of cleaning agents in the toilet, is safer for use in homes with children and pets, and which is preferably portable and compact so that it is easy to seat and not visually undesirable. Further, there is a need in the art for such as system that provides easy dosing and replacement of cleaning agent and/or the actual cleaning system so that systems can be easily replaced, repaired and maintained by consumers without the need for special tools or a plumber.